Vance,
Wow, I really had no idea that what I was suggesting was so taboo.
You make it sound as though I violated some oceanic statute just by
bringing it up. I had tried to stress early on that at 23 I'm a bit
young, and I realize that, but maybe if you can calmly inform me of
any really horrible no no noooo's then possibly you can just drop me
a note or something? Scolding me publicly is hardly a conducive way
to promote the free flow of information and subject matter in a board
which is not governed by insurance policies nor commercial
institutions.
Furthermore... I think that your view of the future of submersible
use, especially by private contractors, is archaic. Actually, I
might leave the dinosaurs out of it and just leave it at "outdated".
I realize that the older crowed here spent alot of time either on the
surface, or on the bottom, but never in a capacity where a diver
might need to exit the sub at a spot somwehere BETWEEN the surface
and the bottom. I'd imagine that I'm a whole new species of human
who can find extremely usefull ideas for establishing a protocol of
correct procedure and safety for exiting and reentering a sub while
in a column of water, and not grounded at the bottom.
I'm sure there are several possible scenarios for the situation. I
like to think "outside the bun". It's a nasty habit that tends to get
me promotions. The more informed I am about several ways I can do
something, the more contingencies I can come up with when I need to
make decisions. I'm not sure that limiting myself with conventional
taboos is necessary.
I also like to be safe though.
Ken
vbra676539@aol.com wrote:
We've been through this. no, No, No, NOOOOOOO!!!!! The boat WILL NOT
be neutral, or even close to it while a diver is outside. Live
boating, as moving the sub while the diver is outside is called, is
strictly forbidden by insurance companies, commerical dive procedures
and common sense. You build the boat to flood negative in excess of
the BOTH diver's weights, as your tender may in fact have to get out
to serve as rescue or back-up diver. Mid-water diving??? Sheesh! Come
on, guys. Vance
-----Original Message-----
From: ShellyDalg@aol.com
To: personal_submersibles@psubs.org
Sent: Fri, 25 May 2007 12:51 am
Subject: Re: [PSUBS-MAILIST] VBT's
Hi. This is in response to the diver weight compensation question.
Every dive trip in your sub requires careful measurement of what you
bring on-board.
If the dive plan calls for a diver to exit the sub while at depth, I
would think that it would be better to add buoyancy to cover the
divers extra weight while on-board, and then dump that buoyancy ( air
bubble ) when the diver exits the sub, there-by maintaining neutral
buoyancy while the diver is outside.
When the diver is back on-board, blow the required amount of air
back into the trim tank ( a measured amount of water to compensate
for exactly how much the diver weighs ) and again maintaining neutral
buoyancy.
A sub with a diver lock-out function would need a bigger trim tank
than a sub without that capability.
Don't forget to calculate how much air the diver displaces with his
body, as this will figure into the required additional buoyancy too.
You don't need a separate pump system, nor would that be desirable,
to let a diver exit and re-enter the sub. The lock-out chamber is
controlled by air pressure, and any small amount of water that
remained within would be easily compensated for by the additional
trim tank volume.
You WILL need some means of dumping the air from the lock-out
chamber once the water is blown out and the hatch is closed so the
diver is once again at one atmosphere. This needs to be monitored
closely so a diver has time to dump the excess nitrogen absorbed by
his body tissues and blood. A diver lock-out chamber is really much
like a de-compression chamber, but is located inside another chamber
( the sub's pressure hull ) so a compressor to drive out the
additional air is required.
Frank D.
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